Ultralightweight Base Layers

Which material is best?

• Wool: highly moisture-wicking and odor-resistant
• Synthetic: durable and less expensive
• Silk: soft and lightweight for casual activities

Match the temp to the trek

• Lightweight layers: best for moderate to cool temperatures
• Midweight layers: best for cold temperatures
• Heavyweight layers: best for below-freezing temperatures

Find your fit

• Must be close to skin to efficiently wick sweat; should fit comfortably snug
• Base layer is for moisture control; your mid layer is for warmth

Fabrics

• Synthetic: moisture-wicking, quick drying, durable, but can hold on to odor
• Wool: moisture-wicking, odor-resistant, cooling in warm weather, can be less durable

Styles

• Bikini: less rear coverage, thinner waistband, higher-cut leg
• Briefs (women's): full-cut briefs offer more coverage in front and back; hipsters offer medium front coverage and back with higher rise

• Briefs (men's): close fit and good support, but less thigh coverage

• Boxer brief or boy shorts: snug fit, good coverage, longer cut extends down to the upper thigh
• Boxers: looser fit, added coverage can prevent chafing but prone to bunching
• Thongs: lightweight and quick-drying but provide the least coverage
• Sports bras: compression and support during high-output activities like hiking and running