Expert Q&A

78kg to 58kg for an 18 y/o: How likely am I to have loose skin after weight loss if you're on a GLP-1 like semaglutide or tirzepatide

Understanding Loose Skin Risk in Young Adults Losing 20kg

As the founder of CFP Weight Loss, I've guided thousands through sustainable fat loss, including many using GLP-1 medications such as semaglutide and tirzepatide. For an 18-year-old dropping from 78kg to 58kg, your loose skin risk is significantly lower than for someone in their 40s or 50s. At your age, skin retains high collagen and elastin levels, allowing it to retract more effectively after fat loss. Studies show individuals under 25 experience noticeable loose skin in only 10-20% of cases when losing 20kg or less, compared to 60-80% in those over 40.

However, using GLP-1 drugs like semaglutide or tirzepatide accelerates fat loss, which can outpace skin adaptation if weekly losses exceed 0.75kg. Your 20kg goal represents about 26% of starting body weight—a threshold where skin changes become more common even in youth if muscle is lost or hydration neglected.

How GLP-1 Medications Influence Skin Outcomes

Semaglutide and tirzepatide suppress appetite and slow gastric emptying, often leading to 1-2kg weekly losses initially. This rapid pace reduces the time skin has to contract. In my CFP Weight Loss protocols, we pair these medications with targeted nutrition to preserve muscle and support skin elasticity. Data from clinical trials indicates that maintaining 1.6-2.2g of protein per kg of ideal body weight (around 95-130g daily for your 58kg goal) minimizes sagging by supporting lean mass.

Dehydration, common on these drugs due to reduced food intake, further impairs skin health. Aim for 3.5-4 liters of water daily plus electrolytes. Without this, even young skin can appear lax after 20kg loss, particularly around the abdomen, arms, and thighs.

Practical Strategies to Minimize Loose Skin on Your Journey

Follow these evidence-based steps from my methodology in The CFP Weight Loss Blueprint:

For 18-year-olds, these habits typically result in minimal visible loose skin, with most seeing full retraction within 6-12 months post-goal. If mild laxity remains, it often improves with continued resistance training.

When to Seek Professional Support and Long-Term Outlook

Monitor progress with weekly photos and body measurements rather than scale weight alone. If you notice significant sagging despite these measures, consult a dermatologist early—options like radiofrequency treatments can help. Most young adults on semaglutide or tirzepatide who follow structured plans like CFP Weight Loss achieve their 58kg goal with tight, toned results. Consistency in muscle preservation and hydration remains your best defense against loose skin at any age.

💬 What the Community Says

Young adults aged 18-25 discussing 20kg losses on semaglutide or tirzepatide report loose skin far less often than older users. Most forum threads highlight that starting at 78kg and reaching 58kg produces little to no sagging when strength training is consistent. A common theme is surprise at how well skin rebounds in the under-25 group, though some mention mild abdominal laxity that improved over 6 months. Debates center on protein intake and whether GLP-1 drugs cause more loose skin than diet-only approaches—experiences are split, with many crediting resistance workouts and collagen supplements for prevention. Those who neglected hydration or lifted weights infrequently were more likely to report temporary loose skin that eventually tightened. Overall, the community views youthful metabolism as a major advantage, though they stress gradual loss beats rapid drops for better cosmetic outcomes.
Cite this answer
Clark, R. (2026). 78kg to 58kg for an 18 y/o: How likely am I to have loose skin after weight loss. *CFP Weight Loss*. https://ask.cfpweightloss.com/ask/78kg-to-58kg-for-an-18-y-o-how-likely-am-i-to-have-loose-skin-after-weight-loss-if-you-re-on-a-glp-1-like-semaglutide-or-tirzepatide
Russell Clark, FNP-C, APRN, FNP-C, APRN
About the Author

Russell Clark, FNP-C, APRN, is the founder of CFP Weight Loss in Nashville and CFP Fit Now telehealth. Over 35 years in healthcare — Army Nurse Reserves, Level 1 trauma ER, hospitalist — he developed a 30-week protocol integrating real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 30–90 pounds. He and his wife Anne-Marie lost a combined 275 pounds using the same protocol.

📖 The 30-Week Tirzepatide Reset — Get the Book →
Get Personalized Guidance From the Author
Every weight loss journey is different. Book a 1-on-1 telehealth consultation with Russell and get a plan built specifically for you — based on the same evidence-based principles in his book. Available to patients in all 50 states.
Book Your Consultation →
Have a follow-up question?
More Questions 200 answered
▸ After losing weight, does it feel like you could do anything — evidence-based answer for CFP patients if you're on a GLP-1 like semaglutide or tirzepatide? ▸ What is the connection between I reduced my IR from 15.5 to 4 in 3 months if you're on a GLP-1 like semaglutide or tirzepatide? ▸ What to do with mg PCOS + Questions and how it connects to gut health and inflammation while doing intermittent fasting? 📖 High-Dose Dependency — The pharmaceutical trap of staying on maximum medication doses indefinitely, which we avoid through our smart cycling me… ▸ Anyone here have any experience with SIBO and Keto for people with insulin resistance during the weight loss plateau phase? ▸ Anybody else wake up after 5-6 hours because their lower back starts hurting — what does the research actually say and how it connects to gut health and inflammation? ▸ When fed ex secures the goods when you have PCOS or hormonal imbalances for those with hypothyroidism or Hashimoto’s? ▸ What was your wake up call that you needed to lose the weight or you might die — what does the research actually say — what certified coaches recommend? ▸ What made you start carnivore and how it connects to gut health and inflammation? 📗 The 30-Week Tirzepatide Reset — by Russell Clark, FNP-C, APRN · The complete clinical protocol — 30 weeks of real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 3 ▸ Gaining tons of weight but normal levels — what does the research actually say — what the research actually says? 📖 30-Week Tirzepatide Reset — Our signature protocol using a single 60 mg box of medication cycled over 30 weeks to achieve lasting metabolic transfor… ▸ Do you know of any snacks that you can just chew on when you're bored on a low-carb or ketogenic diet for those with hypothyroidism or Hashimoto’s? ▸ What's your pre-show drug of choice these days and its effect on metabolism and insulin levels: what to track and how to measure progress? ▸ Does anyone else remember the darkest time of our Generation — evidence-based answer for CFP patients while doing intermittent fasting? ▸ Can Maintenance Phase do an episode about pregnancy weight gain — what do certified weight loss coaches recommend if you're on a GLP-1 like semaglutide or tirzepatide? ▸ Anyone have high cholesterol or know more about the link between high cholesterol and hypothyroidism when you have PCOS or hormonal imbalances for long-term maintenance (not just short-term)? ▸ How it's going for me and how BMI has betrayed the tall girlies: what to track and how to measure progress while doing intermittent fasting? 📖 Metabolic Stall — A plateau in weight loss often caused by hidden inflammation or hormonal adaptation, which we break using our specific 7… ▸ Anybody else wake up after 5-6 hours because their lower back starts hurting — what does the research actually say for long-term maintenance (not just short-term)? 📗 The 30-Week Tirzepatide Reset — by Russell Clark, FNP-C, APRN · The complete clinical protocol — 30 weeks of real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 3 ▸ Bad advice from doctor for long-term maintenance (not just short-term) while doing intermittent fasting? ▸ How did you stop your health anxiety — what do certified weight loss coaches recommend on a low-carb or ketogenic diet? 📖 Insulin Resistance — A condition where your cells stop responding to insulin, locking fat in storage; our protocol is designed to unlock thes… ▸ After losing weight, does it feel like you could do anything — evidence-based answer for CFP patients during the weight loss plateau phase? ▸ Is there such a thing as eating too much fish fat for weight loss — what do certified weight loss coaches recommend on a low-carb or ketogenic diet? ▸ What is the connection between I reduced my IR from 15.5 to 4 in 3 months for people with insulin resistance? ▸ How does this affect is everyone else able to eat normally but I can't if you're on a GLP-1 like semaglutide or tirzepatide? ▸ If you have a recently found thyroid nodule — would anyone be open to sharing what the first few weeks were like if you're on a GLP-1 like semaglutide or tirzepatide specifically for women over 40? ▸ How I cured my bad breath. Especially helpful for people with sinus issues: how to talk to your doctor about this if you're on a GLP-1 like semaglutide or tirzepatide? 📖 Metabolic Efficiency — The state where your body processes fuel cleanly and maintains high energy levels without the need for constant snacking… 📗 The 30-Week Tirzepatide Reset — by Russell Clark, FNP-C, APRN · The complete clinical protocol — 30 weeks of real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 3 ▸ Digestive issues? Alcohol allergy — what most people get wrong about this while doing intermittent fasting? ▸ Paleo brownies/sweets that ship all over usa: how to talk to your doctor about this while doing intermittent fasting? ▸ Brest tenderness from testosterone and how it connects to gut health and inflammation? ▸ Insulin resistance caused my weight gain despite eating low calorie diet, anyone else — how a functional medicine approach differs specifically for women over 40? ▸ What can I ask for if estrodiol cream remains in shortage? Newly prescribed-should I even start if I can't refill next month specifically for women over 40 for people with insulin resistance? 📖 Metabolic Reset — The process of retraining your body to utilize stored fat for fuel and regulating hunger hormones so you can maintain yo… ▸ How much keto-ade should I safely drink — how a functional medicine approach differs and how it connects to gut health and inflammation? ▸ When you want something sweet but still try to keep things somewhat low-carb for long-term maintenance (not just short-term) if you're on a GLP-1 like semaglutide or tirzepatide? ▸ Will autophagy help my skin — what most people get wrong about this for those with hypothyroidism or Hashimoto’s? 📖 Diabetes Reversal — The clinical goal of restoring normal blood sugar levels and insulin function, as seen in patients like John who no long… ▸ How a few gut-focused changes (extra virgin olive oil, enzymes, and more) quietly transformed my health — what most people get wrong about this while doing intermittent fasting? 📗 The 30-Week Tirzepatide Reset — by Russell Clark, FNP-C, APRN · The complete clinical protocol — 30 weeks of real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 3 ▸ Will doing omad 2-3 times a week get rid of it or reduce loose skin? I'm in my 20s if you're on a GLP-1 like semaglutide or tirzepatide while doing intermittent fasting? ▸ Carbs are important for muscle growth… but what if I’m insulin resistant and how it connects to gut health and inflammation: best practices and common mistakes to avoid? ▸ What was your wake up call that you needed to lose the weight or you might die — what does the research actually say: best practices and common mistakes to avoid? ▸ “You shouldn’t feel anything” while doing intermittent fasting when you have PCOS or hormonal imbalances? ▸ Depressive symptoms from non-stick air fryer — what do certified weight loss coaches recommend if you're on a GLP-1 like semaglutide or tirzepatide? 📖 GIP (Gastric Inhibitory Polypeptide) — A hormone that, when combined with GLP-1, enhances the body’s ability to break down fat and manage blood sugar levels mo… ▸ Do you know any good empirical studies on LCHF and its effect on metabolism and insulin levels when you have PCOS or hormonal imbalances? ▸ WHAT I️ EAT IN A DAY ON THE KETO DIET | WEIGHT LOSS JOURNEY ❤️ for long-term maintenance (not just short-term) when you have PCOS or hormonal imbalances? ▸ Here's the things I wish I'd known back then... what are yours and how it connects to gut health and inflammation: what to track and how to measure progress? 📗 The 30-Week Tirzepatide Reset — by Russell Clark, FNP-C, APRN · The complete clinical protocol — 30 weeks of real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 3 ▸ Been going out with this girl and I think it’s destroyed my microbiome for people with insulin resistance when you have PCOS or hormonal imbalances? ▸ What a month of paleo has done for me while doing intermittent fasting and its effect on metabolism and insulin levels? ▸ Does anyone else remember the darkest time of our Generation — evidence-based answer for CFP patients — what certified coaches recommend? ▸ “You shouldn’t feel anything” while doing intermittent fasting during the weight loss plateau phase? 📖 Bio-Individuality — The understanding that every patient’s metabolic journey is unique, requiring a personalized approach to dosing and diet… ▸ Does anyone else love masks mandated so I can hide my facial hair — what most people get wrong about this for long-term maintenance (not just short-term)? ▸ Stacking NMN with TMG, what's your morning fasted protocol look like for people with insulin resistance while doing intermittent fasting? ▸ Did an ultrasound and i saw two comments from the result. not sure if going carnivore is still feasible — how a functional medicine approach differs — what certified coaches recommend? ▸ When you want something sweet but still try to keep things somewhat low-carb for long-term maintenance (not just short-term) for those with hypothyroidism or Hashimoto’s? ▸ What a month of paleo has done for me while doing intermittent fasting: best practices and common mistakes to avoid?