All three of the keratinocyte media that Lonza offers have similar basal media and supplements and all are serum free, however, slight variations and modifications have made the KGM-Gold® BulletKit® Lonza’s preferred keratinocyte media.

Lonza’s original keratinocyte media was the KGM® Medium.
In the first optimization of this medium, Lonza modified the basal media and added epinephrine and transferrin to create the KGM®-2 Medium.
The KGM®-2 Medium allows for growth of keratinocytes to be up to 20% faster and allows for additional population doublings when compared to cells cultured in the KGM™ Medium.
In the second optimization of this medium, Lonza further modified the basal media and slightly modified the concentration of several growth factors to create the KGM-Gold® Medium. Compared to the KGM® and KGM®-2 Media, the KGM-Gold® Medium supports better growth at low, moderate and high density keratinocyte cultures, allows for higher seeding efficiencies, moderate growth rates, and provides superior morphology for additional population doublings.
Cells cultures in KGM® or KGM®-2 Media can be directly transitioned into KGM-Gold® Medium, however, cells cultured in KGM-Gold® Medium cannot be transitioned to KGM® or KGM®-2 Media. All keratinocytes that Lonza currently offers are isolated in the KGM-Gold® Medium and must be cultured in the KGM-Gold®.

In general, Lonza suggests the use of KGM-Gold® Medium for all keratinocytes unless the researcher is trying to reproduce a scholarly article where KGM® Medium or KGM®-2 Medium was used with either a cell line, cells they isolated on their own, or cells from another source.

On the below datasheet, you can see the supplements included in each of the Keratinocyte Medium BulletKit

Lonza’s standard KGM® and KGM®-2 media both contain calcium at 0.15 mM.
Lonza’s standard KGM-Gold® medium contains calcium at 0.10 mM