{"id":127022,"date":"2026-07-24T14:52:23","date_gmt":"2026-07-24T20:52:23","guid":{"rendered":"https:\/\/purmabiologics.com\/blog\/what-is-hams-f-12k\/"},"modified":"2026-08-26T18:42:39","modified_gmt":"2026-08-27T00:42:39","slug":"what-is-hams-f-12k","status":"publish","type":"post","link":"https:\/\/purmabiologics.com\/blog\/what-is-hams-f-12k\/","title":{"rendered":"What Is Ham&#8217;s F-12K? Kaighn&#8217;s Modification Explained"},"content":{"rendered":"<div class=\"purma-guide\">\n<p class=\"pg-lead\">Ham&#8217;s F-12K (Kaighn&#8217;s modification of Ham&#8217;s F-12) is a nutrient-rich medium designed for demanding cell lines and low-serum culture. It builds on Richard Ham&#8217;s original F-12 formulation, created for the serum-free clonal growth of Chinese hamster ovary (CHO) cells, and adjusts several components for stronger support. This guide explains what F-12K is, how it relates to F-12, what it contains, and which cells it suits.<\/p>\n<div class=\"pg-keyfacts\">\n<h3>Key Facts<\/h3>\n<ul>\n<li><strong>Type:<\/strong> Nutrient-rich medium (Kaighn&#8217;s mod of Ham&#8217;s F-12)<\/li>\n<li><strong>Best for:<\/strong> CHO cells and specialized lines<\/li>\n<li><strong>Notable:<\/strong> Adds putrescine, hypoxanthine, thymidine, zinc<\/li>\n<li><strong>Buffering:<\/strong> Bicarbonate (use a CO2 incubator)<\/li>\n<\/ul>\n<\/div>\n<h2>What is Ham&#8217;s F-12K?<\/h2>\n<p>Ham&#8217;s F-12 is a richly supplemented basal medium first developed by Richard Ham for growing CHO cells with little or no serum. Kaighn&#8217;s modification, known as F-12K, raises the concentration of several amino acids and other components, producing a more nutrient-dense medium that supports a broader set of demanding cells. Like other basal media, F-12K supplies salts, amino acids, vitamins, and glucose, and it is completed with serum and glutamine before use.<\/p>\n<h2>What is in Ham&#8217;s F-12K?<\/h2>\n<p>F-12K is notable for its wide range of components, including:<\/p>\n<ul>\n<li>A broad set of <strong>amino acids<\/strong> at raised concentrations compared with standard F-12<\/li>\n<li>A rich <strong>vitamin<\/strong> profile and added trace elements<\/li>\n<li><strong>Putrescine, hypoxanthine, thymidine, and zinc<\/strong>, components not found in older media<\/li>\n<li><strong>Glucose<\/strong> and a bicarbonate buffer with phenol red, so it needs a CO2 incubator<\/li>\n<\/ul>\n<h2>What is Ham&#8217;s F-12K used for?<\/h2>\n<p>F-12K suits cells that benefit from a rich, well-rounded environment, including:<\/p>\n<ul>\n<li><strong>CHO cells<\/strong> and other lines descended from Ham&#8217;s original F-12 work<\/li>\n<li>Certain <strong>endothelial and specialized cell lines<\/strong><\/li>\n<li>Cultures moving toward reduced-serum conditions<\/li>\n<\/ul>\n<p>Ham&#8217;s F-12 is also widely blended 1:1 with DMEM to make <strong>DMEM\/F-12<\/strong>, a popular medium that pairs DMEM&#8217;s richness with F-12&#8217;s broad component list.<\/p>\n<h2>How to supplement and use Ham&#8217;s F-12K<\/h2>\n<p>Before use, F-12K is completed with serum (commonly 10% FBS) and L-glutamine or a stable glutamine dipeptide. Keep it in a CO2 incubator, store it refrigerated and protected from light, warm it gently before use, and keep the same lot across an experiment for consistency.<\/p>\n<\/div>\n<div class=\"purma-related\">\n<p class=\"pr-h\">Related guides<\/p>\n<ul class=\"pr-list\">\n<li><a href=\"\/what-is-dmem\/\">What Is DMEM?<\/a><\/li>\n<li><a href=\"\/what-is-dmem-f12\/\">What Is DMEM\/F-12?<\/a><\/li>\n<li><a href=\"\/what-is-emem\/\">What Is EMEM?<\/a><\/li>\n<\/ul>\n<p class=\"pr-all\">Browse every guide in the <a href=\"\/cell-culture-guides\/\">Cell Culture Guides library<\/a>.<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Ham&#8217;s F-12K (Kaighn&#8217;s modification of Ham&#8217;s F-12) is a nutrient-rich medium designed for demanding cell lines and low-serum culture. It builds on Richard Ham&#8217;s original F-12 formulation, created for the serum-free clonal growth of Chinese hamster ovary (CHO) cells, and adjusts several components for stronger support. This guide explains what F-12K is, how it relates [&hellip;]<\/p>\n","protected":false},"author":3155,"featured_media":127119,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[856],"tags":[],"class_list":["post-127022","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","entry","has-media","owp-thumbs-layout-horizontal","owp-btn-normal","owp-tabs-layout-horizontal","has-no-thumbnails","has-product-nav"],"acf":[],"_links":{"self":[{"href":"https:\/\/purmabiologics.com\/blog\/wp-json\/wp\/v2\/posts\/127022","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/purmabiologics.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/purmabiologics.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/purmabiologics.com\/blog\/wp-json\/wp\/v2\/users\/3155"}],"replies":[{"embeddable":true,"href":"https:\/\/purmabiologics.com\/blog\/wp-json\/wp\/v2\/comments?post=127022"}],"version-history":[{"count":0,"href":"https:\/\/purmabiologics.com\/blog\/wp-json\/wp\/v2\/posts\/127022\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/purmabiologics.com\/blog\/wp-json\/wp\/v2\/media\/127119"}],"wp:attachment":[{"href":"https:\/\/purmabiologics.com\/blog\/wp-json\/wp\/v2\/media?parent=127022"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/purmabiologics.com\/blog\/wp-json\/wp\/v2\/categories?post=127022"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/purmabiologics.com\/blog\/wp-json\/wp\/v2\/tags?post=127022"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}