Overview Leaderboard Methodology
Industry Report

Vitamin D Supplements

Standalone vitamin D3 or D2 products sold to support bone health, immune function, and vitamin D deficiency prevention.

Brands tracked: 32
Brands analyzed: 32
Last updated: 2026-04-23
Model: OpenAI GPT-5
Prompts: 252
Total responses: 1,285
Top Brand Overall?
Nature Made
86/100

Highest overall AI Visibility Score in this industry.

LBA Leader?
Thorne
86

Highest score on the LBA metric in this industry.

Authority Leader?
Nature Made
81

Highest score on the Authority metric in this industry.

TOM Leader?
Nature Made
100

Highest score on the TOM metric in this industry.

Nature Made is the default answer in AI responses for Vitamin D Supplements

When users ask ChatGPT, Claude, or Gemini about Vitamin D Supplements, Nature Made is the brand that surfaces first - unprompted, consistently, and usually at the top of any list the model generates. Thorne is a close second, but the gap between them is meaningful. If you're competing in this space and you're not in the top handful, you're effectively invisible to AI-driven discovery.

Brand Leaderboard All 32 Vitamin D Supplements brands ranked

Ranked by overall AI Visibility Score (smoothed geometric mean of LBA, Authority, and TOM with an LBA-based floor on Authority and TOM, see methodology). Click any brand for the full report.

# Brand LBA Authority TOM Overall
1
Nature Made
naturemade.com
 78
81
100
86
2
Thorne
thorne.com
 86
33
100
66
3
Carlson
carlsonlabs.com
 68
30
83
56
4
Garden of Life
gardenoflife.com
 70
13
36
33
5
Nordic Naturals
nordic.com
 75
8
43
31
6
Sports Research
sportsresearch.com
 78
8
41
31
7
Pure Encapsulations
pureencapsulationspro.com
 80
8
28
28
8
Solgar
solgar.com
 79
8
27
28
9
Kirkland Signature
costco.com
 81
11
13
24
10
Life Extension
lifeextension.com
 83
8
12
22
11
Jarrow Formulas
jarrow.com
 79
8
8
19
12
MaryRuth's
maryruthorganics.com
 77
8
8
19
13
Jamieson
jamiesonvitamins.com
 73
7
7
18
14
Vitabiotics
vitabiotics.com
 74
7
7
18
15
Designs for Health
designsforhealth.com
 68
7
7
17
16
D
Doctor's Best
doctorsbest.com
 63
6
6
16
17
Equate
walmart.com
 65
6
6
16
18
BetterYou
betteryou.com
 60
6
6
15
19
D
Ddrops
ddrops.com
 59
6
6
15
20
NOW Sports
nowfoods.com
 62
6
6
15
21
Seeking Health
seekinghealth.com
 60
6
6
15
22
Source Naturals
sourcenaturals.com
 62
6
6
15
23
Webber Naturals
webbernaturals.com
 60
6
6
15
24
ChildLife Essentials
childlife.com
 56
6
6
14
25
Swanson
swansonvitamins.com
 55
5
5
14
26
Kirkman
kirkmanlabs.com
 50
5
5
13
27
Natrol
natrol.com
 54
5
5
13
28
NatureWise
naturewise.com
 54
5
5
13
29
B
Bio-Tech Pharmacal
biotechpharmacal.com
 39
4
4
10
30
Z
Zahler
zahler.com
 38
4
4
10
31
Bronson
bronsonvitamins.com
 35
3
3
9
32
Eu Natural
eunatural.com
 22
2
2
6

How is this calculated? Methodology

Every brand in this leaderboard is scored against the same set of 252 shared Vitamin D Supplements prompts. The same prompts, same model, same iterations. So differences in scores reflect actual differences in AI visibility, not differences in measurement.

Overall AI Visibility Score
Smoothed geometric mean of LBA, Authority and TOM. Authority and TOM are floored at LBA × 0.1 before the geometric mean (the same floor used in the per-metric cards above, so brand cards and the composite tell the same story). Formula: composite = ((LBA + 5)(Authority + 5)(TOM + 5))^(1/3) - 5. The floor keeps brands the model clearly recognises but doesn't yet recommend from collapsing to zero, while a single genuinely weak metric still pulls the composite down. Full methodology.
Shared industry prompts
For Authority and TOM, all brands in the industry are scored against the same 252 category prompts (e.g. "best SEO tools for agencies"). This makes brand-to-brand comparisons valid - everyone faces identical inputs. LBA prompts are per-brand because they ask brand-specific questions.
Latent Brand Association (LBA)
5 brand probes + 1 control prompt, each run 5 times in recall mode (no web search). LBA = quality × meta × stability × share × recognition × 100. Read the full LBA methodology →
LLM Authority
50 organic category prompts (discovery, comparison, problem and transactional intents), each run once in recall mode and once in retrieval mode. Score = frequency × log-decayed prominence × intent weight, then 50/50 averaged across the two modes. Read the full Authority methodology →
Top of Mind (TOM)
15 high-volume discovery prompts (sourced from Keywords Everywhere search-volume data), each run 5 times in pure recall mode (no web). Score = frequency × (0.5 + 0.5 × log-prominence), volume-weighted. Read the full TOM methodology →