Do stretch marks mean weight loss or weight gain?

Why can both weight gain and weight loss cause them?

A stretch mark is a scar that forms when skin stretches or shrinks quickly. That abrupt change can rupture collagen and elastin, the structures that support skin. The marks appear as skin heals. Weight gain stretches skin as body size increases; rapid weight loss can involve the opposite change. Speed matters here: both rapid gain and rapid loss are recognised triggers, rather than stretch marks being a sign of only one direction.12

Not everyone develops stretch marks after these changes. Family history increases the likelihood, and changing hormone levels seem to play a role. Long term use of some steroid creams or tablets can also contribute. Weight related stretching is a mechanical cause, not a way to diagnose your weight or health from the marks alone.134

Does their colour tell you anything?

Colour is more useful for recognising newer versus older marks than for identifying weight gain versus loss. New marks can be pink, red, purple, reddish brown or dark brown, depending on skin colour. They can feel slightly raised and itchy. Older marks usually fade and become slightly sunken; some turn silver or white and develop a wrinkled surface. A pale mark can therefore remain after the change that originally caused it.12

What should you do if you notice new marks?

1. 1Consider recent changes, including rapid weight gain or loss, pregnancy, puberty or muscle growth.
2. 2Note when the marks appeared and which medicines you use, including steroid skin creams. These are details a clinician will ask about.
3. 3Contact a healthcare provider if there is no clear cause. If your weight has changed dramatically without explanation, mention that too.

Will they fade, and do you need treatment?

Stretch marks are common and harmless, so treatment is optional. They usually become less visible over time, but fading is not the same as removing the scar. Many creams claim to remove stretch marks despite little evidence that they work, so the label is doing more lifting than the formula. Maintaining a healthy weight can reduce the chance of developing them, but prevention is not always possible.3

If you want to reduce their appearance, treatment is more useful on new marks than mature ones. Hyaluronic acid and prescription tretinoin can help make early marks less noticeable; retinol can also help. For a suitable stretch mark cream or gel, gently massage it in and use it daily as directed. Visible improvement takes weeks, not days. A dermatologist can discuss laser treatment or other procedures for persistent marks, although these cannot erase them.137

Do not use retinoid creams during pregnancy. If you are pregnant or breastfeeding, check with your doctor before treating stretch marks. Retinol can cause dryness, irritation, itching or burning and increases sensitivity to sunlight, so use sunscreen if you use it.137

When should you see a doctor?

Arrange an appointment for unexplained marks, especially large marks alongside increased fat around the chest and tummy with slim arms and legs, fat around the back of the neck and shoulders, or a red, puffy, rounded face. This combination can indicate Cushing's syndrome, a condition involving high cortisol levels. Unexpected weight gain also needs assessment if you gain 2 to 3 pounds a day, 5 pounds a week, or at least 5% of your body weight in a month.356