Both fibers deserve a place in your closet. The real question isn't which is "better" in some abstract sense—it's which one fits your life. Commuting in Boston? Different answer than trail running in Colorado. Let's break it down honestly.
Quick Comparison Overview
Alpaca Strengths
- 3-5x warmer per unit weight
- Softer (18-22 micron baby alpaca)
- No lanolin — hypoallergenic
- Lighter garments for same warmth
- Lower environmental footprint
- Naturally odor-resistant
Merino Strengths
- Superior elasticity and stretch
- Better moisture-wicking for athletics
- Wider availability, more brands
- Lower price point generally
- Better for base layers and activewear
- Excellent shape recovery
Warmth: Alpaca Wins
This isn't close. Alpaca fibers are hollow—picture thousands of microscopic tubes trapping pockets of warm air against your body. Merino fibers are solid. That structural difference translates to roughly three to five times more thermal efficiency per unit of weight.
What that means in practice: a thin alpaca sweater can match a much heavier merino one for warmth. I own a baby alpaca pullover that weighs barely anything and outperforms my thickest merino mid-layer on winter hikes. The difference is startling the first time you feel it.
Worth knowing
Alpaca also retains heat when damp, similar to merino. But because it's lighter for the same warmth level, you're carrying less weight on the trail or around town. For cold-climate daily wear, that hollow fiber structure is a genuine advantage.
Elasticity & Stretch: Merino Wins
Here's where merino pulls ahead, and it matters more than you'd think. Merino wool has a natural crimp—a built-in spring that lets it stretch and snap back. That's why merino base layers fit like a second skin and recover their shape after every wash.
Alpaca doesn't have that crimp. It drapes beautifully, but it won't hug your body the way a merino athletic shirt does. Over time, knitted alpaca garments can stretch slightly at stress points (elbows, cuffs). Good construction mitigates this, but it's a real consideration.
For running, cycling, yoga, or any activity where you need fabric that moves with you and bounces back? Merino is the better choice. It's also why brands like Smartwool and Icebreaker built entire athletic lines around merino, not alpaca.
Softness & Comfort
Fiber diameter determines how soft something feels against your skin. Baby alpaca measures 18-22 microns. Fine merino runs 17-22 microns. On paper, they're comparable. In reality, alpaca feels smoother.
Why? Alpaca fiber has a smoother scale structure than merino. Those tiny overlapping scales on wool fibers are what cause the prickle some people feel. Alpaca's scales are flatter and less pronounced, so it glides against skin rather than catching. People with lanolin sensitivities or mild wool allergies can usually wear alpaca without issues.
I've handed both fibers to dozens of people blind and asked them to pick the softer one. Alpaca wins about 80% of the time—especially baby alpaca grade. If softness is your top priority, you'll want to read our alpaca vs cashmere comparison too.
Sustainability & Ethics
Both fibers have genuine environmental merits compared to synthetics. Both are biodegradable, renewable, and long-lasting. But the specifics differ.
Alpacas are lighter on the land. Their padded feet don't churn up topsoil the way sheep hooves do. They graze by cutting grass at the top rather than ripping roots out. A herd of alpacas on Andean grassland causes minimal erosion. And alpacas produce enough fiber from a single annual shearing to make several garments—they're efficient.
Merino sheep farming, particularly in Australia and New Zealand, operates at massive scale with higher water and land demands. That said, the merino industry has made real strides in sustainable grazing practices over the past decade. Neither fiber is environmentally "bad." Alpaca just has a lighter footprint overall, particularly when sourced from traditional Peruvian highland communities.
The Verdict: It Depends on Your Needs
Choose alpaca if warmth, softness, and hypoallergenic comfort are your priorities. For sweaters, scarves, cardigans, blankets, and cold-weather layering, it's the superior fiber. You'll pay a bit more upfront, but the garment will outlast most merino equivalents.
Choose merino if you need performance athletic wear, base layers, or stretchy garments that recover their shape. Merino's elasticity and moisture management are genuinely better for high-activity use. It's also more budget-friendly and easier to find.
Plenty of people—myself included—own both. An alpaca sweater for the office and weekends, merino base layers for the mountain. They're complementary fibers, not rivals.
Frequently Asked Questions
Which is better, merino wool or alpaca wool?
Neither is universally better—it depends on your priorities. Alpaca is warmer, softer, lighter, and hypoallergenic (no lanolin). Merino has better elasticity, is easier to find, more affordable, and better for athletic wear due to moisture-wicking. For everyday warmth and luxury, alpaca wins. For active wear and budget, merino is the practical choice.
Is alpaca warmer than merino wool?
Yes, alpaca is approximately 3-5 times warmer than merino per unit of weight. The hollow fiber structure in alpaca traps more air, creating superior insulation. This means an alpaca sweater can be thinner and lighter while providing the same warmth as a heavier merino garment.
Is alpaca wool better than lambswool?
For most uses, yes. Alpaca is softer, warmer, lighter, and hypoallergenic compared to lambswool. Lambswool contains lanolin (potential allergen), is heavier, and coarser. Lambswool's advantage is lower price and wider availability. For quality garments, alpaca is the superior choice.