diff --git a/sw/qa/core/text/EnhancedPDFExportHelper.cxx b/sw/qa/core/text/EnhancedPDFExportHelper.cxx
index c5effb0056df..e57d18436dd4 100644
--- a/sw/qa/core/text/EnhancedPDFExportHelper.cxx
+++ b/sw/qa/core/text/EnhancedPDFExportHelper.cxx
@@ -204,6 +204,42 @@ CPPUNIT_TEST_FIXTURE(Test, testTOCItemRef)
     // one item per heading, each naming its own
     CPPUNIT_ASSERT_EQUAL("H1 H2 "_ostr, aTargets.makeStringAndClear());
 }
+
+CPPUNIT_TEST_FIXTURE(Test, testFormulaAltFromSource)
+{
+    createSwDoc("formula-alt.fodt");
+    // a formula reaches the export loaded, not running, in every document but a freshly typed one
+    saveAndReload(TestFilter::ODT);
+
+    uno::Sequence aFilterData{ comphelper::makePropertyValue(u"UseTaggedPDF"_ustr, true) };
+    save(TestFilter::PDF_WRITER,
+         { comphelper::makePropertyValue(u"FilterData"_ustr, aFilterData) });
+
+    vcl::filter::PDFDocument aDocument;
+    maTempFile.CloseStream();
+    CPPUNIT_ASSERT(aDocument.Read(*maTempFile.GetStream(StreamMode::READ)));
+
+    OUStringBuffer aAlts;
+    for (const auto& rDocElement : aDocument.GetElements())
+    {
+        auto pObject = dynamic_cast<vcl::filter::PDFObjectElement*>(rDocElement.get());
+        if (!pObject)
+            continue;
+
+        auto pType = dynamic_cast<vcl::filter::PDFNameElement*>(pObject->Lookup("S"_ostr));
+        if (!pType || pType->GetValue() != "Formula")
+            continue;
+
+        // Without the fix a formula nobody had described carried no Alt, which the PDF/UA
+        // checkers count against the file
+        auto pAlt = dynamic_cast<vcl::filter::PDFHexStringElement*>(pObject->Lookup("Alt"_ostr));
+        CPPUNIT_ASSERT(pAlt);
+        aAlts.append(vcl::filter::PDFDocument::DecodeHexStringUTF16BE(*pAlt) + "|");
+    }
+
+    // the source where nobody described the formula, and the title where somebody did
+    CPPUNIT_ASSERT_EQUAL(u"E=mc^2|Half of a|"_ustr, aAlts.makeStringAndClear());
+}
 }
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sw/qa/core/text/data/formula-alt.fodt b/sw/qa/core/text/data/formula-alt.fodt
new file mode 100644
index 000000000000..d040e95b3c55
--- /dev/null
+++ b/sw/qa/core/text/data/formula-alt.fodt
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<office:document xmlns:office="urn:oasis:names:tc:opendocument:xmlns:office:1.0" xmlns:style="urn:oasis:names:tc:opendocument:xmlns:style:1.0" xmlns:text="urn:oasis:names:tc:opendocument:xmlns:text:1.0" xmlns:draw="urn:oasis:names:tc:opendocument:xmlns:drawing:1.0" xmlns:fo="urn:oasis:names:tc:opendocument:xmlns:xsl-fo-compatible:1.0" xmlns:svg="urn:oasis:names:tc:opendocument:xmlns:svg-compatible:1.0" xmlns:math="http://www.w3.org/1998/Math/MathML" office:version="1.3" office:mimetype="application/vnd.oasis.opendocument.text">
+ <office:font-face-decls>
+  <style:font-face style:name="Liberation Serif" svg:font-family="'Liberation Serif'" style:font-family-generic="roman" style:font-pitch="variable"/>
+ </office:font-face-decls>
+ <office:styles>
+  <style:default-style style:family="paragraph">
+   <style:text-properties style:font-name="Liberation Serif" fo:font-size="12pt" fo:language="en" fo:country="US"/>
+  </style:default-style>
+  <style:style style:name="Standard" style:family="paragraph" style:class="text"/>
+ </office:styles>
+ <office:automatic-styles>
+  <style:style style:name="fr1" style:family="graphic">
+   <style:graphic-properties style:vertical-pos="middle" style:vertical-rel="text" fo:padding="0in" fo:border="none"/>
+  </style:style>
+ </office:automatic-styles>
+ <office:body>
+  <office:text>
+   <text:p text:style-name="Standard">The mass energy equivalence is <draw:frame draw:style-name="fr1" draw:name="Object1" text:anchor-type="as-char" svg:width="0.9in" svg:height="0.3in" draw:z-index="0"><draw:object><math:math><math:semantics><math:mrow><math:mi math:mathvariant="normal">E</math:mi><math:mo math:stretchy="false">=</math:mo><math:msup><math:mi math:mathvariant="italic">mc</math:mi><math:mn>2</math:mn></math:msup></math:mrow><math:annotation math:encoding="StarMath 5.0">E=mc^2</math:annotation></math:semantics></math:math></draw:object></draw:frame> in a paragraph.</text:p>
+   <text:p text:style-name="Standard">A described one is <draw:frame draw:style-name="fr1" draw:name="Object2" text:anchor-type="as-char" svg:width="0.6in" svg:height="0.4in" draw:z-index="1"><draw:object><math:math><math:semantics><math:mrow><math:mfrac><math:mi math:mathvariant="italic">a</math:mi><math:mn>2</math:mn></math:mfrac></math:mrow><math:annotation math:encoding="StarMath 5.0">a over 2</math:annotation></math:semantics></math:math></draw:object><svg:title>Half of a</svg:title></draw:frame> here.</text:p>
+  </office:text>
+ </office:body>
+</office:document>
diff --git a/sw/source/core/text/EnhancedPDFExportHelper.cxx b/sw/source/core/text/EnhancedPDFExportHelper.cxx
index 288476cf1b10..492dc4242bb1 100644
--- a/sw/source/core/text/EnhancedPDFExportHelper.cxx
+++ b/sw/source/core/text/EnhancedPDFExportHelper.cxx
@@ -22,13 +22,16 @@
 #include <algorithm>
 #include <unordered_map>
 
+#include <com/sun/star/embed/EmbedStates.hpp>
 #include <com/sun/star/embed/XEmbeddedObject.hpp>
 #include <com/sun/star/i18n/ScriptType.hpp>
 #include <com/sun/star/drawing/XShape.hpp>
 #include <com/sun/star/beans/XPropertySet.hpp>
 #include <hintids.hxx>
 
+#include <comphelper/scopeguard.hxx>
 #include <sot/exchange.hxx>
+#include <svtools/embedhlp.hxx>
 #include <vcl/outdev.hxx>
 #include <vcl/pdfextoutdevdata.hxx>
 #include <vcl/pdf/PDFNote.hxx>
@@ -453,6 +456,45 @@ const SwTextNode* lcl_JumpedToNode(const SwEditShell& rSh, const SwPosition& rBe
     return rPoint == rBeforeJump ? nullptr : rPoint.GetNode().GetTextNode();
 }
 
+// the StarMath source of the formula a frame holds, empty for anything else
+OUString lcl_GetFormulaSource(const SwFlyFrame& rFly)
+{
+    if (!rFly.Lower() || !rFly.Lower()->IsNoTextFrame())
+        return OUString();
+
+    const SwContentNode* pNode = static_cast<const SwNoTextFrame*>(rFly.Lower())->GetNode();
+    SwOLENode* pOLENd = pNode ? const_cast<SwOLENode*>(pNode->GetOLENode()) : nullptr;
+    if (!pOLENd)
+        return OUString();
+
+    const uno::Reference<embed::XEmbeddedObject> xObj(pOLENd->GetOLEObj().GetOleRef());
+    if (!xObj.is() || !SotExchange::IsMath(SvGlobalName(xObj->getClassID())))
+        return OUString();
+
+    OUString aSource;
+    try
+    {
+        // a loaded object has no component to read the source from
+        const bool bWasLoaded(xObj->getCurrentState() == embed::EmbedStates::LOADED);
+        if (!svt::EmbeddedObjectRef::TryRunningState(xObj))
+            return OUString();
+
+        // reading it ran the object, and an export leaves the document as it found it
+        const comphelper::ScopeGuard aRestore([&xObj, bWasLoaded] {
+            if (bWasLoaded)
+                xObj->changeState(embed::EmbedStates::LOADED);
+        });
+
+        const auto xProps(xObj->getComponent().query<beans::XPropertySet>());
+        if (xProps.is())
+            xProps->getPropertyValue(u"Formula"_ustr) >>= aSource;
+    }
+    catch (const uno::Exception&)
+    {
+    }
+    return aSource;
+}
+
 // the node a table of contents entry links to, which the mark in its URL names
 const SwTextNode* lcl_GetLinkedNode(const SwDoc& rDoc, const SwTextNode& rEntry)
 {
@@ -1113,11 +1155,17 @@ void SwTaggedPDFHelper::SetAttributes(vcl::pdf::StructElement eType)
         // text here again.
         if (bAltText)
         {
-            SwFlyFrameFormat const& rFly(*static_cast<SwFlyFrame const*>(pFrame)->GetFormat());
+            SwFlyFrame const& rFlyFrame(*static_cast<SwFlyFrame const*>(pFrame));
+            SwFlyFrameFormat const& rFly(*rFlyFrame.GetFormat());
             OUString const sep(
                 (rFly.GetObjTitle().isEmpty() || rFly.GetObjDescription().isEmpty())
                 ? OUString() : u" - "_ustr);
-            OUString const altText(rFly.GetObjTitle() + sep + rFly.GetObjDescription());
+            OUString altText(rFly.GetObjTitle() + sep + rFly.GetObjDescription());
+            // a formula nobody described names its own source
+            if (altText.isEmpty() && eType == vcl::pdf::StructElement::Formula)
+            {
+                altText = lcl_GetFormulaSource(rFlyFrame);
+            }
             if (!altText.isEmpty())
             {
                 mpPDFExtOutDevData->SetAlternateText(altText);