It's one of the most Googled questions about Gymshark: does it run small?
The short answer is: it depends on the range. Gymshark's sizing is notoriously inconsistent between product lines. Here's what real UK women actually found.
Gymshark sizing by product line
Vital Seamless Leggings
True to size for most. Women in UK 10–16 generally find the Vital fits as expected. The exception: if you have wider hips (40"+ or UK 14+), the fabric pulls across the thighs and many recommend sizing up one.
Flex Leggings
Runs small. The Flex has minimal stretch recovery compared to the Vital. Most reviewers — across all body types — recommend sizing up. A UK 12 typically fits better in a Gymshark M (which is their UK 12–14 equivalent).
Energy Seamless
True to size, stretchy. The Energy range is more forgiving. Women with hourglass and pear shapes both find it accommodating. Sizing up is only needed if you're right on the boundary.
Speed 5" Shorts
True to size. The built-in compression liner is the useful part — it extends longer than the outer shell. Most women find their regular size works well, with only those at 40"+ hips needing to go up.
Sport Defined Bra
Runs small — size up always. This is consistently the most complained-about item in terms of sizing. The band is narrow and the cups are small. Women with a D cup or above almost universally say to size up at least one, sometimes two.
Gymshark size chart: UK conversions
| Gymshark Size | UK Size (approx) | Bust | Waist | Hips |
|---|---|---|---|---|
| XS | 6–8 | 31–33" | 24–26" | 33–35" |
| S | 8–10 | 33–35" | 26–28" | 35–37" |
| M | 10–12 | 35–37" | 28–30" | 37–39" |
| L | 12–14 | 37–39" | 30–32" | 39–41" |
| XL | 14–16 | 39–41" | 32–34" | 41–43" |
| 2XL | 16–18 | 41–43" | 34–36" | 43–45" |
| 3XL | 18–20 | 43–46" | 36–39" | 45–48" |
What body shape matters most
Gymshark leggings are cut for a narrower hip-to-thigh ratio than many UK women have. Pear shapes and plus sizes are most likely to find the standard size too snug across the hips and thighs, even if the waist fits well.
Hourglass shapes tend to find Gymshark a good fit — the waist definition in seamless ranges suits a defined waist-to-hip ratio.
Rectangle/athletic shapes generally find Gymshark true to size across all ranges.
The bottom line
- Leggings (Vital, Energy): size as normal unless you have wider hips — then size up
- Leggings (Flex, Adapt): size up one from your usual UK size
- Bras: size up one — especially if D cup or above
- Shorts: true to size
For a personalised recommendation based on your measurements, take the Forre fit quiz and see what women with your body shape bought.