As more Australians embark on medical weight loss treatments, many trainers now find themselves training clients on weight loss medication without fully understanding what these drugs do, how they affect exercise performance, or what’s within their professional scope. Clients may casually mention, “I’ve just started Ozempic,” leaving trainers torn between curiosity, concern and confusion. In this guide, I’ve aimed to provide a non-biased, clinical overview of GLP-1 medications, their implications for training, and the key risks and opportunities they should be aware of.
What Are GLP-1 Weight Loss Medications and How Do They Work?
GLP-1 medications (short for glucagon-like peptide-1 receptor agonists), are drugs originally developed to treat Type 2 Diabetes Mellitus (T2DM). They mimic the action of the body’s natural GLP-1 hormone, which plays a role in appetite, digestion, and blood glucose regulation.
Common GLP-1 drug names:
- Semaglutide – brands: Ozempic, Wegovy
- Tirzepatide – brand: Mounjaro (technically a dual GLP-1/GIP agonist, not a pure GLP-1)
- Liraglutide – brand: Saxenda
How they differ:
Semaglutide
- Once-weekly injection using pen device
- Strong appetite suppression
- Significant average weight loss found in clinical trials
- Larger impact on slowing gastric emptying which can cause more gastrointestinal (GI) side effects early on, compared to Mounjaro
- Work predominantly within the large bowel
Ozempic
– Used off-label as a weight loss medication, originally intended for the treatment of diabetes only
– Maximum dose 1mg
– Average weight loss found in research – 12%
Wegovy
– On-label weight control
– Maximum dose 2.4mg
– Average weight loss found in research 17%
– More expensive than Ozempic
Tirzepatide (Mounjaro):
- Also once-weekly injection
- Acts on two gut-hormone pathways (GLP-1 + GIP)
- Works on the small bowel and therefore often found to have less gastrointestinal side effects and is therefore better tolerated
- Generally, leads to even greater weight-loss percentages
- Can have accelerated strength or energy dips due to rapid appetite reduction
Liraglutide (Saxenda):
- Daily injection
- Less potent for weight loss
- Still an option when weekly injections are unsuitable
How they work in the body
In simple terms, GLP-1s:
- Reduce appetite sharply – People eat far less, creating a calorie deficit which contributes to weight loss. This is the desired outcome, but in my experience, it can have major implications for training and daily activities due to a resulting lack of energy.
- Slow gastric emptying – Food and drink stay in the stomach longer, reducing hunger and prolonging the feeling of “being full”. The potential downside to this is nausea, especially after exercise as blood flow focuses on the areas it is required e.g. the legs, slowing digestion further.
- Improve insulin sensitivity and blood glucose regulation – This can reduce the negative impact of energy dips but it may also blunt hunger cues further resulting in under fuelling.
- Change body composition during weight loss – Without adequate resistance training and protein intake, more muscle and bone can be lost along with the desired fat loss. This means it is even more of a priority for clients to continue lifting heavy weights and performing some form of bone-loading exercise whilst taking weight loss medication.
A couple of key points to remember are that these medications are not fat burners, metabolism boosters, or stimulants; they are not shortcuts. They change appetite psychology and physiology, not energy expenditure. For best results, people need to pair GLP-1s with improved lifestyle habits such as diet and exercise which is why they still need trainers or fitness coaches.
Inside Your Scope vs Outside Your Scope as a Trainer
Before diving into programming, trainers need to remember where their professional boundaries sit, especially with medications that have real medical risks.
Inside your scope
- Be aware of which medication and dose your client is on, as well as the timing of any dose increases.
- Adjust training volume and exercise selection accordingly, and consider any side effects your client may be experiencing
- Educate clients about the role of resistance training in preserving lean mass and bone density
- Reinforce general nutrition principles (protein, hydration, regular eating), NOT prescribe diets – this should only be done by a dietician
- Monitor fatigue, performance dips, and recovery
- Communicate with a GP or specialist with the client’s consent
- Know the red flags that require medical review
Outside your scope
- Advising on medication dosing, timing, or brands
- Interpreting blood work
- Telling clients whether they should stay on or stop a medication
- Prescribing specific caloric intake, macro targets or supplements
- Diagnosing GI, cardiac or metabolic complications
GLP-1s sit squarely within the medical domain. Your job is to coach movement, monitor training tolerance, and help clients maintain their muscle and metabolic health while in a calorie-restricted state.
Key Physiological Considerations for Clients on GLP-1s
This is the section most trainers wish they understood when their first client walked in and said, “I’ve started taking Ozempic”.
- Risk of muscle loss
GLP-1s do not discriminate between fat and muscle when weight drops.
Without strength training and protein support:
- Up to 30 – 50% of weight lost can be lean mass
- Strength declines quickly
- Metabolic rate decreases
- Functional capacity suffers
Your priority is building and maintaining muscle while the medication reduces appetite.
- Bone health
Rapid weight loss combined with reduced nutrient intake increases the risk of:
- Bone mineral density decline
- Stress fractures
- Reduced impact tolerance
This is particularly pertinent in post-menopausal women, an increasingly common GLP-1 demographic.
- GI side effects
Common yet manageable
- nausea
- reflux
- dehydration
- headache
- dyspepsia/reflux/burping
- constipation
- diarrhoea
- early satiety
Uncommon
- vomiting
- abdominal pain
- significant dehydration
- hair loss (temporary)
These are often experienced in the early weeks, or when the dose is increased. Inconsistent meal timing can also contribute to the above. These side effects can understandably impact training timing and intensity. I usually find that clients feel better after training but might be a bit anxious during warm up if they feel nauseous.
- Hydration challenges
Reduced food intake = reduced water intake.
Clients may under-hydrate without realising.
This affects:
- blood pressure
- heart rate
- endurance training
- heat tolerance
- constipation causing abdominal discomfort
Make sure you’re including water breaks in your programming and encouraging adequate hydration, especially during Australian summers.
- Energy unpredictability
Some clients feel great.
Others feel flat, light-headed or unable to hit previous loads and levels of training intensity.
Expect variability week to week, especially after a dose increase. In my experience, the best thing is to check in with your client before every session and alter training accordingly, being sure to reassure them if they’re not hitting their previous load/intensity.
- Psychological impacts
Many clients experience:
- reduced food focus (helpful) – often described as less “food noise”
- reduced interest in social eating and potential aversion to alcohol
- mild anxiety around nausea
- scale-obsessed behaviour (“the medication needs to work”) – this may feel like a “last chance” for some people who have previously tried many other methods with no success
Trainers should be aware of these factors but avoid stepping into counselling territory. I know that this is the part I’ve previously found difficult, try and be a support without feeling the need to “fix” problems.
- Benefits for Women With PCOS and During Perimenopause/Menopause
Women with Poly Cystic Ovarian Syndrome (PCOS) or those transitioning through perimenopause and menopause often face hormonal shifts that make weight management, inflammation, and metabolic health harder to navigate. GLP-1 medications can offer meaningful support by targeting some of these underlying mechanisms.
How GLP-1s help in PCOS:
- PCOS is strongly linked with insulin resistance, chronic low-grade inflammation, and difficulty losing adipose tissue.
- GLP-1s improve insulin sensitivity, which can reduce circulating insulin levels (a major driver behind weight gain, cravings, and hormonal disruption in PCOS).
- Reductions in visceral and total adipose tissue can help lower systemic inflammation, which may support better ovulatory function and more stable hormonal patterns.
How GLP-1s help in peri/menopause:
- As oestrogen levels fluctuate and decline, fat distribution shifts toward central/visceral storage, increasing cardiometabolic risks.
- Losing visceral fat can help improve metabolic markers, reduce inflammatory load, and support more stable mood and energy levels.
- Lower adiposity can also help prevent excessive peripheral conversion of androgens to oestrogen (via aromatase in fat tissue), which contributes to hormonal imbalance during this life stage.
Why this matters for coaches:
Women in these categories aren’t simply “trying to lose weight”. They’re managing complex hormonal transitions. GLP-1s can give them a metabolic head start, but your role is to help them build the strength, consistency, and lifestyle habits that maintain long-term health once medication tapers or stops.
Programming Priorities: Protect Muscle, Bone and Function
When training clients on weight loss medication, the programming goal is simple:
Preserve (and ideally build) lean mass and bone density while calories naturally drop.
- Strength training is non-negotiable
Minimum target: 2 – 3 full-body sessions/week
Ideal: 3 – 4 structured sessions with progressive overload.
Focus on:
- major compound lifts
- tempo and control
- strength over metabolic fatigue
- moderate reps (5 – 10)
- adequate rest (2 – 3 minutes)
- Prioritise time under tension over high heart rate
Clients are already in a calorie deficit. Don’t bury them with excessive HIIT.
HIIT isn’t off-limits, but it’s no longer the main course. Be guided by what your client can handle and how they recover in between sessions
- Build grip-friendly, joint-friendly progressions
Rapid weight loss may lead to joint discomfort or tendon irritability.
Include:
- slow eccentrics
- isometrics
- stable loading patterns
- good warm-up structure
- Don’t chase volume for the sake of “burning calories”
Old-school weight-loss programming relied on sweat and fatigue.
“Sweat is just fat cells crying” Sound familiar??
While on GLP-1s, your client doesn’t need extra calorie burn – they need anabolic stimulus.
- Consider bone loading
Include impact and load-bearing variations where appropriate:
- marching loaded carries
- step-downs
- small jumps (if trained and appropriate)
- moderate loading in squats/deadlifts
- Individualise based on side effects
E.g. If nausea is present, lean into:
- machines
- lower-intensity options
- seated movements
- be cautious with any head-down movements or changing from supine to upright
- shorter sessions
Practical Nutrition Talking Points (Within Scope)
You’re not a dietitian or GP, but you can reinforce fundamentals that every allied health professional would agree with.
Your scope-appropriate nutrition reminders:
- Protein matters more than ever
Aim for “a good source of protein at every meal.”
Not numbers, not grams – just habits.
Examples to mention:
- chicken, fish, tofu, Greek yogurt, lean meats, legumes
- Eat even if you don’t feel hungry
Clients may unintentionally under fuel as they don’t feel hungry.
Encourage small, regular and well-balanced meals. - Hydration is crucial
“Carry a water bottle” is within scope.
Electrolytes are fine to mention, not prescribe. Hydration also helps manage any constipation - Fibre matters for constipation
Reinforce whole foods, fruit, veg, and whole grains. - Don’t train fasted especially if experiencing any nausea
Suggest small, bland foods beforehand, e.g.:
- crackers
- toast
- a small banana
- Avoid extreme dieting on top of medication
Calorie stacking (medication + huge deficit) = fast muscle loss.
You’re reinforcing safety, not prescribing diet plans.
Session Design When a Client Is on Weight Loss Medication
This is often where trainers feel most lost, so let’s break it down clearly.
Warm-up
- a longer, gentle warm-up helps nausea
- breathing and mobility
- slow ramping of intensity
Main lifts
- 1 – 2 compound lifts first (squat, hinge, press, pull)
- aim for quality sets, not fatigue
- moderate loads (RPE 6 – 8)
- progress weekly, not session-to-session. Always remember to check in before a session to see if clients are experiencing any new side effects or have increased their dose, don’t assume they’ll tell you without prompting
Accessory work
Great place for:
- single-leg variations
- rowing variations
- glute strengthening
- core stability
- mid-back/posture
Conditioning
Think:
- sleds
- incline walking
- zone 2 intervals
- controlled EMOMs
Avoid intense HIIT on days with nausea or after dose increases.
Session duration
In my experience, I find it best to keep this flexible.
Some clients feel best with:
- 30 minute sessions
- two shorter sessions per week
- longer sessions once they stabilise
Adaptability is key.
Safety, Ethics and Red Flags
Clients on GLP-1s are medically managed. Your role is to be vigilant and refer when needed.
Red flags! Refer when you see:
- persistent vomiting
- dizziness or fainting
- ongoing resting tachycardia
- rapid or excessive weight loss
- inability to meet protein/fluid needs
- new abdominal pain
- severe fatigue
- clients taking medication not prescribed to them
Ethical considerations
- Avoid praising extreme weight loss. You can be supportive, but be careful about glorifying decreased kgs on the scales
- Reinforce health, function and strength over scale weight
- Make it clear you are not giving medical advice
- Encourage regular follow-up with the prescribing GP or specialist
- Watch for disordered-eating behaviours masked as “the medication is working”
Documentation and communication
If working in a studio or gym but especially if running your own business:
- Record relevant disclosures
- Keep notes on modified training
- Get written consent to communicate with allied health professionals
Business and Communication Tips for PTs
GLP-1s aren’t a trend – they’re part of the future fitness landscape. Trainers who respond calmly, professionally and knowledgeably will stand out.
How to communicate well
- “These medications can reduce appetite more than people realise. Let’s make sure your training protects your strength and bone health.”
- “If anything feels different this week, tell me. Side effects can change with dosage.”
- “We’re focusing on performance and strength as your body weight changes.”
Build alliances and networks around you
- Connect with local GPs, endocrinologists and dietitians
- Position yourself as a safe, evidence-based trainer
- Provide progress notes when relevant
Marketing positioning (ethically)
Avoid “GLP-1 specialist” claims.
You can say:
- “Experienced in strength training for clients undergoing medical weight-loss treatment”
- “Evidence-informed coaching for people using weight-loss medications under medical care”
Long-term retention
Clients on GLP-1s often need coaching more, not less:
- to protect muscle mass
- to rebuild confidence
- to maintain results when the dose stabilises or decreases
This is an opportunity to support clients holistically while staying firmly within scope.
Training clients on weight loss medication doesn’t have to be intimidating. When you understand how GLP-1s affect appetite, digestion, energy and body composition, you can coach confidently without stepping into medical territory.
Your priority is simple but crucial:
Preserve strength, muscle, bone density and function while supporting safe, sustainable training habits.
Thanks to Caroline Jones for this article.
Caroline is a physiotherapist with two decades of experience spanning acute hospital care, oncology rehabilitation and lymphoedema management. She is passionate about using exercise as medicine and getting patients moving, especially those living with chronic conditions.
She also holds a Level 3 Certificate in Personal Training, owns a CrossFit box with her husband, and enjoys being a below-average runner.
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